griteater

GFS has a really dynamic look to it for western NC (that's where I was focused - could be in other areas too). From a thermal standpoint, you can see a squeeze play going on as this system develops - the 850 zero degree line is working its way NW and backing right into the cold air in W NC....long duration event on the GFS...ya'll have winter storm warnings in the NC mtns yet? You need them

I have visions of a new lessons learned thread appearing soon

It's a bit too warm near the sfc IMO. I didn't realize the HRRR had warmed when I typed that. That warming makes more sense to me in all honesty

Weird to me that the GFS and Euro globals are warmer than the hi-res HRRR and NAM (GSP to CLT). It's usually the other way around. It being flipped would make sense if we had cold air damming....but we don't * Stands up and flips table *

Gulf sea surface temperatures are above normal. It's going to be a good ol fashioned, slow moving, gulf low with long SW flow moisture fetch. Not a wound up system with convection robbing and splotchy radar coverage...my thoughts anyway

I like 1-3 there

I would go 1-3

That's crazy. GFS has precip from tonight into Saturday aftn for the upstate

Just a follow up to say that a stronger system with stronger sfc low and stronger 850mb wave/low will, in fact, show more warm nosing....this is not much of an issue for Bama and GA, but would be more of an issue as you go east as the GFS shows with a stronger system now.

I mean, it basically always ends up this way right? Frosty, Jonathon, and Big Frosty sad and moping, saying they can't buy QPF, and they end up with the good stuff.....ha, all in fun Buddy - good luck your way!

Interesting there how it shows the strong omega (red bars on left) higher up in the 300-500mb range....indicative of the strong divergence from a very strong jet streak aloft over the northeast

We say "it's a tough call" a lot, but the HRRR and latest NAMs suggest that this is a tough call for the GSP to CLT corridor. Conservative forecast would be to go with rain, with a chance for snow to mix in. The soundings suggest that when the precip is heavy, it could very well flip to snow (I looked at Simpsonville). There is a lot of discussion about the warm nose...but I wanted to point out that the warm bubble east of Atlanta over into the upstate is where there is a pocket of above freezing air in the lower levels of the atmosphere (cold air having a tough time moving in over the mtns). As precip falls and we go toward morning, the sounding shows cooling of this lower level warmth, down to where it could be cold enough for snow. This is different from what is traditionally referred to as a warm nose where warm air is pouring in aloft from the southeast at the 850-750mb levels. In that case, the sounding shows the warmth aloft 'nosing' above freezing as opposed to lower level warmth above freezing. Bottom line: having the above freezing warm layer closer to the ground is easier to overcome than warm air pouring in aloft from the southeast. The text below is the scenario we are looking for here. That is, the 850mb low isn't closed and strong with our storm tomorrow and the warm advection aloft is staying closer to the SE coast than it is pouring inland (source - http://www.wxonline.info/topics/preciptype.html ) "Melting of Snow to Rain" "Melting snow to rain requires latent heat. This heat is taken from the surrounding air. In order to obtain substantial temperature change due to melting, it is necessary to have rather heavy amounts of precipitation falling with little or no warm advection. If this occurs, you can have heavy rain turn to heavy snow as the freezing level sinks downward due to cooling by latent heat absorption. Although this situation can occur, cases of substantial lowering of the freezing level due to melting are relatively rare because the combination of heavy precicpitation without warm air advection is rare."

Birmingham is an area that struggles to get good setups for snow. Good chance IMO that you see some with this system with some light accumulations

I tell you what, my confidence is fairly high that Lake Toxaway is going to see a good wallop of snow from this....hoist the Winter Storm Warnings there Isohume!

You had it correct though...that's the 12z RGEM thru hr 48, then it kicks in with the CMC Global after 48hr

This is like an exact climo southeast snowstorm...why do we need to spend 80 hours a day looking at this stuff

You can throw the SC mtns in there with NC and GA mtns, ha...Caesar's Head

The Euro just locks the 35-37 degree type temperatures and dewpoints for the entire storm east of Atlanta to upstate to southern foothills to southern piedmont.....doesn't budge a millimeter

My own analysis of where the Euro is supportive of snow (without regard for the snow map or precip type algorithm on the model): 1AM Fri: Snow in GA and NC Mtns, and northern NC foothills 7 AM Fri: Snow just N and NW of ATL into SE TN, GA and NC Mtns, northern NC foothills 1PM Fri: Snow NW side of ATL metro into NW and N Central GA into SE TN, GA and NC Mtns, northern NC foothills 7PM Fri: Snow NW side of ATL metro, GA and NC Mtns, northern foothills, NW Triad 1AM Sat: Snow NW side of ATL metro, GA and NC Mtns, northern foothills, Hickory to NW Triad 7AM Sat: Snow N side of CLT to Hickory to Triad Just S and E of these areas, there could be some snow where precip bursts and cools the column...or rain/snow mix Having said all of that, I wouldn't be surprised to see the Euro a little warmer than this on the 00z run

For your area it has decent precip into Sat AM, winding down late morning / lunch

The Euro moved NW with precip...it now has 0.5-0.6 along the eastern Blue Ridge escarpment.

Here are the Charlotte surface observations from the Nov 2000 storm. It probably won't be this cold, but similar setup relying on precip to cool the lowest warm layer in the atmosphere http://mp1.met.psu.edu/~fxg1/NARR/2000/us1119.php

Looking at the isobars there, you can see how Alabama and Georgia have more northerly wind component trying to feed in cold air...whereas SC and central NC are struggling in that department

It looks a whole lot like tonight's CMC and GFS based on the early maps...more detailed maps come out later

As long as the system doesn't just collapse on the models, yeah, it usually nudges NW at the end. Had weaker model runs this aftn and evening, but we still have a storm